JSFiddle - React, Tailwind, and code Playground

HTML

<div id="dvMap" style="width: 500px; height: 500px">

JavaScript

<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyAlGSdMz1_B7qXVrcAugcPQ0Y5plrHPcb4&libraries=geometry"></script>
    <script>
    "use strict";
    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(
            function(position) {

                var markers = @Html.Raw(Json.Encode(Model.UpcomingLectureGigs));
                var currentLatitude = position.coords.latitude;
                var currentLongitude = position.coords.longitude;
                var userLatLng = currentLatitude + currentLongitude;
                var markersFiltered = markers.filter(function(markers, index, array, google) {
                var myLatlng = new window.google.maps.LatLng(markers.Latitude, markers.Longitude);

                    return google.maps.geometry.spherical.computeDistanceBetween(userLatLng, myLatlng) < 10000;
                });
                window.onload = function(a) {
                    var mapOptions = {
                        center: new window.google.maps.LatLng(markers[0].Latitude, markers[0].Longitude),

                        zoom: 8,
                        mapTypeId: window.google.maps.MapTypeId.ROADMAP
                    };

                    var infoWindow = new window.google.maps.InfoWindow();
                    var map = new window.google.maps.Map(document.getElementById("dvMap"), mapOptions);

                    for (var i = 0; i < markersFiltered.length; i++) {
                        var data = markers[i];
                        var myLatlng = new window.google.maps.LatLng(data.Latitude, data.Longitude);
                        var marker = new window.google.maps.Marker({
                            position: myLatlng,
                            draggable: true,
                            animation: google.maps.Animation.DROP,
                            get map() { return map; }
                        });
                        (function(marker, data) {
                           ...